If we do not get ICS in the coming months I might have to give it a shot. I am hesitant because there doesnt seem to be a stable ICS Rom with working 4G. That and well I messed up a Nexus S 4G I had for messing with ROMS.
I kept mine stock for about a week before unlocking the bootloader and ROMming it. But if you've accepted the 2.3.5 update you can no longer unlock so you'll have to use bootstrap recovery to flash a custom ROM on it.